Optimus-claude unit-test

Improves unit test coverage on demand — discovers testing gaps and generates tests that follow project conventions. Requires /optimus:init to have set up test infrastructure first. Conservative — only adds new test files, never refactors existing source code. Supports `deep harness` mode for an automated multi-cycle unit-test + testability-refactor loop with fresh context per phase. Use when test coverage is low, after adding new code that lacks tests, or when you want an automated coverage-improvement harness.

install

source · Clone the upstream repo

git clone https://github.com/oprogramadorreal/optimus-claude

Claude Code · Install into ~/.claude/skills/

T=$(mktemp -d) && git clone --depth=1 https://github.com/oprogramadorreal/optimus-claude "$T" && mkdir -p ~/.claude/skills && cp -r "$T/skills/unit-test" ~/.claude/skills/oprogramadorreal-optimus-claude-unit-test && rm -rf "$T"

manifest: skills/unit-test/SKILL.md

source content

Unit Test Coverage Improvement

Improve unit test coverage for existing code. Requires

/optimus:init

to have set up test infrastructure (framework, coverage tooling, testing docs) first. Conservative by design — only adds new test files, never refactors or restructures existing source code. If code is untestable as-is, it flags it rather than changing it. Refactoring is the domain of

/optimus:refactor

Step 1: Pre-flight

Parse invocation arguments

Extract from the user's arguments:

```
deep
```
flag (present/absent)
```
harness
```
keyword after
```
deep
```
(present/absent)
A number immediately after
```
deep
```
or
```
deep harness
```
→ cycle cap (optional, default 5, hard cap 10)
Everything else → scope instructions (optional path)

Examples:

```
/optimus:unit-test
```
→ normal mode, full project
```
/optimus:unit-test src/api
```
→ normal mode, scoped
```
/optimus:unit-test deep
```
→ deep mode (5 cycles)
```
/optimus:unit-test deep 3
```
→ deep mode (3 cycles)
```
/optimus:unit-test deep harness
```
→ harness mode, 5 cycles

/optimus:unit-test deep harness 5 "src/api"

→ harness mode, scoped

Harness mode detection

If system prompt contains

HARNESS_MODE_ACTIVE

: → Read

$CLAUDE_PLUGIN_ROOT/references/coverage-harness-mode.md

→ Follow the "Unit-Test Phase Execution" section → Skip user confirmation (no

AskUserQuestion

) → Skip loops — run Steps 2–4 exactly once, then output structured JSON and stop

harness

keyword detected in arguments: → Read

$CLAUDE_PLUGIN_ROOT/references/coverage-harness-mode.md

Skill-Triggered Invocation section → Pass:

max_cycles

(from step 1 parsing),

scope

(from step 1 parsing) → The invocation section will resolve the Python environment, build the terminal command pointing to

scripts/test-coverage-harness/main.py

, present it, and stop → Do NOT proceed to Step 2

Pre-flight checks

Read

$CLAUDE_PLUGIN_ROOT/skills/init/references/multi-repo-detection.md

for workspace detection. If a multi-repo workspace is detected, process each repo independently: run Steps 1-5 inside each repo that has

.claude/CLAUDE.md

. Report results per repo. If no repos have been initialized, suggest running

/optimus:init

first from the workspace root.

Check that

.claude/CLAUDE.md

exists. If it doesn't, stop and recommend running

/optimus:init

first — the project needs baseline context before test generation can be effective.

Beyond the init check, identify which guideline documents are available — they directly affect the quality of everything this skill does:

Document	Role	Effect on skill
`coding-guidelines.md`	Primary quality reference	Tests follow naming conventions, code structure, quality standards
`testing.md`	Testing conventions	Framework, runner commands, mocking patterns, file organization
`.claude/CLAUDE.md`	Project overview	Tech stack signals, test runner commands

Monorepo path note: Read the "Monorepo Scoping Rule" section of

$CLAUDE_PLUGIN_ROOT/skills/init/references/constraint-doc-loading.md

for doc layout and scoping rules. When generating tests for a subproject, load that subproject's

testing.md

, not another subproject's.

The skill operates differently depending on what exists:

All three docs — matches existing conventions precisely
CLAUDE.md + coding-guidelines (no testing.md) — derives conventions from the codebase
CLAUDE.md only (no guidelines either) — still works, but with less project-specific guidance

Scope

Parse optional path argument (e.g.,

/optimus:unit-test src/api

) to limit scope. If no path is specified, default to the full project.

For monorepos and multi-repo workspaces, detect project structure using the same approach as

/optimus:init

— reference

$CLAUDE_PLUGIN_ROOT/skills/init/SKILL.md

Step 1 for detection logic (multi-repo workspace detection, workspace configs, manifest scanning, supporting signals). Process each project/repo independently.

Step 2: Discovery & Coverage Analysis (agent-assisted)

Delegate test infrastructure scanning, test execution, and coverage analysis to a reconnaissance agent to keep the main context clean for test writing.

For each subproject (or the single project):

Read

$CLAUDE_PLUGIN_ROOT/skills/unit-test/agents/shared-constraints.md

for agent constraints. Read

$CLAUDE_PLUGIN_ROOT/skills/unit-test/agents/test-infrastructure-analyzer.md

for the full prompt template, scanning patterns, execution rules, and return format for the Test Infrastructure Analyzer Agent.

Launch 1

general-purpose

Agent tool call using the prompt from test-infrastructure-analyzer.md, prepended with the shared constraints.

Agent	Role	Runs when
1 — Test Infrastructure Analysis	Scan test files/frameworks/runners, run existing tests, measure coverage, classify code testability	Always

Wait for the agent to complete.

Stop gates (evaluated from agent results)

If no test framework is detected in the agent's Discovery Results, stop and report: "No test framework found. Run

/optimus:init

(or re-run it) to install a test framework and set up test infrastructure before using this skill." Do not proceed to test generation without a working framework.

If the agent's Test Suite Execution reports failures, stop. This skill does not fix failing tests or build-level issues by design. Print the matching message below (Conversation / Mode / Next skill per

$CLAUDE_PLUGIN_ROOT/references/skill-handoff.md

Fail - assertion (tests compile and run, but some fail): print the quote below, then append a
```
### Bugs Discovered
```
section listing each failing test as
```
[test file] — [test name] — [one-line failure excerpt]
```
(prefix entries with repo name/path in multi-repo workspaces; omit the excerpt if the test runner output did not expose it).
Pre-existing tests are failing. A green baseline is required before adding new tests, and this skill does not modify existing tests or source code.

Next: stay in this conversation (normal mode) and ask Claude to triage the failing tests listed in Bugs Discovered. Once the baseline is green, start a fresh conversation and re-run
```
/optimus:unit-test
```
.

Tip: for best results, start a fresh conversation for the next skill — each skill gathers its own context from scratch.
Fail - build (build/bootstrap failures): print the quote below and stop — no Bugs Discovered section (there are no per-test failures to list, only build errors the analyzer has already summarized).
The test runner cannot start or test files fail to compile. These are build-level issues, not test logic, and
```
/optimus:init
```
owns that repair path.

Next: start a fresh conversation in normal mode and run
```
/optimus:init
```
— its health check will propose minimal fixes and re-run the suite. Once the build is healthy, start another fresh conversation and re-run
```
/optimus:unit-test
```
.

Tip: for best results, start a fresh conversation for the next skill — each skill gathers its own context from scratch.

Present to user

From the agent's results, present the Discovery Summary and Coverage Analysis to the user. This sets clear expectations and reinforces the conservative constraint.

Data carried forward

Test runner command and framework identity → Step 4 (test execution and idioms)
Coverage tooling → Step 5 (final measurement)
Testability classification → Step 3 (plan prioritization — testable items become candidates, untestable items are skipped)
Baseline coverage → Step 5 (before/after comparison)

Step 3: Test Generation Plan

Create a prioritized list, capped at 10 items per run:

Exported/public functions and classes — API surface, highest value
Pure functions and utility modules — easiest to test, highest ROI
Business logic with clear inputs/outputs — core functionality
Complex branching logic — high cyclomatic complexity, most likely to have bugs
Internal/private helpers — lower priority, test through public API when possible

Skip (flag in summary, don't attempt):

Code that's untestable without refactoring
Generated code (protobuf, OpenAPI, ORM migrations)
Migration files
Declarative configuration
Thin wrappers with no logic

User confirmation

Deep mode (harness or interactive): Skip the question — auto-select "Generate tests for all planned items" and proceed directly to Step 4.

Normal mode: Present the plan, then use

AskUserQuestion

— header "Plan", question "How would you like to proceed with the test generation plan?":

Approve all — "Generate tests for all planned items"
Selective — "Choose specific items by number"
Skip — "No tests — keep the plan as reference"

If the user selects Selective, ask which item numbers to proceed with (e.g., "1, 3, 5").

Step 4: Test Writing

Quality standards

Tests must follow:

```
coding-guidelines.md
```
for quality standards (naming, structure, clarity)
```
testing.md
```
for testing conventions (framework idioms, file naming, directory structure)
```
$CLAUDE_PLUGIN_ROOT/skills/tdd/references/testing-anti-patterns.md
```
for mocking discipline — prefer real code over mocks, never assert on mock behavior, mock only external services or non-deterministic dependencies
Existing test files for concrete patterns to replicate: import style, assertion library, file naming convention, directory placement, shared fixtures (conftest/setup files, factories, beforeAll/setUp blocks), and describe/it or class/method test organization. Extract these patterns before writing the first test and apply them consistently to all generated tests.

Before writing each test

Answer these gate questions — fix any "no" before proceeding:

File placement — Does a test file for this module already exist? If yes, add tests there instead of creating a new file. New files must follow the naming convention from
```
testing.md
```
(typically
```
test_<module_name>
```
or
```
<module_name>.test
```
).
Fixtures and helpers — Do existing test files or shared setup files (conftest.py, test helpers, factories) already provide fixtures for the data this test needs? Use them instead of creating private helpers that duplicate existing setup.
Mocking and assertion discipline — apply the gate questions from
```
$CLAUDE_PLUGIN_ROOT/skills/tdd/references/testing-anti-patterns.md
```
(already referenced in Quality standards above).
Setup duplication — apply the DRY principle from
```
coding-guidelines.md
```
to test setup: repeated setup should be extracted to shared fixtures (setUp/beforeEach, conftest, factories).

Conservative constraint

Only add new test files. Never refactor or modify existing source code — refactoring is the domain of

/optimus:refactor

. If a function can't be tested without changing its signature or extracting dependencies, flag it in the summary instead of changing it.

Per-test workflow

For each approved item:

Write the test file
Self-review against the "Before writing each test" checklist above — fix any violations before running
Run it immediately
If the test fails:
- Fix the test (not the source code) — max 3 fix attempts
- If still failing after 3 attempts, flag as untestable and move on
- If the failure reveals an actual bug in existing code, report the bug but do not fix it
Move to the next item

Final verification

After all tests are written, run the full test suite to ensure no regressions. Follow the verification protocol from

$CLAUDE_PLUGIN_ROOT/skills/init/references/verification-protocol.md

— run tests fresh, read complete output, and report actual results with evidence before claiming success.

Step 5: Summary

Report to the user:

## Unit Test Summary

### Coverage
- Coverage tooling: [tool name / not configured]
- Before: [X]% → After: [Y]%
- Achievable target (without refactoring): ~[Z]%

### Tests Created
| # | File | Target | Status |
|---|------|--------|--------|
| 1 | src/__tests__/auth.test.ts | auth module exports | ✓ Pass |
| 2 | src/__tests__/validate.test.ts | validation utilities | ✓ Pass |
| ... | ... | ... | ... |

### Bugs Discovered
- [List of bugs found in existing code — reported, not fixed]

### Not Testable Without Refactoring
- [List of code flagged as untestable — with brief explanation of what structural change would be needed]
- To address these, run `/optimus:refactor testability` to prioritize testability improvements.

For multi-repo workspaces, present results per repo (one summary block per repo) and include the repo name/path in each section header.

Recommend running

/optimus:refactor testability

to prioritize testability improvements (or

/optimus:refactor

for balanced code quality review), or

/optimus:tdd

to continue development with test-driven workflow.

Tell the user: Tip: for best results, start a fresh conversation for the next skill — each skill gathers its own context from scratch.

Step 6: Harness Output (harness mode only)

If running under

HARNESS_MODE_ACTIVE

, output structured JSON instead of the Step 5 markdown summary. Output it in a

json:harness-output

fenced block and then stop — do not loop, do not present recommendations, do not use

AskUserQuestion

```json:harness-output
{
  "iteration": <cycle number from progress file>,
  "phase": "unit-test",
  "coverage": {
    "tool": "<coverage tool name or null>",
    "before": <percentage or null>,
    "after": <percentage or null>,
    "delta": <percentage or null>
  },
  "tests_written": [
    {
      "file": "<test file path>",
      "target_file": "<source file being tested>",
      "target_description": "<what it tests>",
      "test_count": <number of test cases>,
      "status": "<pass | fail-fixed | fail-abandoned>",
      "failure_reason": "<reason or null>"
    }
  ],
  "untestable_code": [
    {
      "file": "<source file path>",
      "line": <start line>,
      "end_line": <end line>,
      "function": "<function or class name>",
      "barrier": "<hardcoded-dependency | tight-coupling | global-state | ...>",
      "barrier_description": "<brief explanation>",
      "suggested_refactoring": "<what refactoring would help>"
    }
  ],
  "bugs_discovered": [
    {
      "file": "<path>",
      "line": <line>,
      "description": "<bug behavior>",
      "severity": "<High | Medium | Low>"
    }
  ],
  "no_new_tests": <true if zero new tests were written>,
  "no_untestable_code": <true if no untestable code was found>,
  "no_coverage_gained": <true if coverage delta is zero or negative>
}
```